Eagleman opens chapter six with a description of an incident in Austin, Texas in 1966. Charles Whitman, a twenty-five-year-old man, shot forty-six people from the top of a tower on the University of Texas campus, killing thirteen of them. Police climbed the tower and killed Whitman. His body was examined afterward and it was found that he had a small tumor in his brain that impacted a part of the brain called the amygdala, which is involved in the regulation of emotions such as aggression and fear.

In writings he left behind, Whitman indicated that he suspected he had something wrong with his brain, hoping that his body might be studied. People who knew him had noticed that his behavior had changed in the months leading up to his shooting...